The cashew is a tree in the family Anacardiaceae. Its English name derives from the Portuguese name for the fruit of the cashew tree, caju, which in turn derives from the indigenous Tupi name, acajú.
Originally native to northern South America, it is now widely grown in tropical climates for its cashew seeds and cashew apples. The tree is small and evergreen, growing to 10-12m (~32 ft) tall, with a short, often irregularly shaped trunk. The leaves are spirally arranged, leathery textured, elliptic to obovate, 4 to 22 cm long and 2 to 15 cm broad, with a smooth margin. The flowers are produced in a panicle or corymb up to 26 cm long, each flower small, pale green at first then turning reddish, with five slender, acute petals 7 to 15 mm long. The largest cashew tree in the world covers an area of about 7,500 square metres (81,000 sq ft). The fruit of the cashew tree is an accessory fruit (sometimes called a pseudocarp or false fruit). What appears to be the fruit is an oval or pear-shaped structure that develops from the pedicel and the receptacle of the cashew flower.
The cashew nutshell liquid (CNSL), a byproduct of processing cashew, is mostly composed of anacardic acids (70%), cardol (18%) and cardanol (5%). These acids have been used effectively against tooth abscesses due to their lethality to a wide range of Gram-positive bacteria.[